Older patients often suffer functional decline during hospitalization for acute illness, which leads to dependence, worsened quality of life, and, sometimes, institutionalization or death. No past study has provided compelling evidence that functional decline can be prevented or ameliorated during acute hospitalization. The proposed interventional study addresses this gap in knowledge. The long-term objective is to identify a comprehensive yet practical intervention that can prevent functional decline in hospitalized older patients. In a prospective preliminary study, the course of functional decline in acutely ill, hospitalized older patients was defined: decline in ADL function occurred in 36% of patients, began shortly before admission, worsened in the hospital, and had serious sequelae. Functional decline was conceptualized in the framework of ecological models that highlight the importance of congruence between older people and their environment. A comprehensive intervention to lessen functional decline -- the "Prehab Program of Patient-Centered Care" -- was then designed and implemented on a 15-bed Unit for the Acute Care of the Elderly (ACE Unit). Prehab is nurse-initiated at admission, and has six preventive and rehabilitative elements: the prepared environment of the ACE Unit; interdisciplinary, collaborative care; multidimensional assessment and non-pharmacologic prescription to maintain or restore functional independence; review of procedures and medications; planning to go home, involving the patient's informal caregiving network; transitional care to continue the gains of Prehab after discharge. Preliminary data on 400 patients strongly suggest that in addition to lessening functional decline, Prehab may decrease hospital charges and length of stay up to 20%. The specific aim of the proposed study is to determine the efficacy of the ACE Unit's Prehab Program in acutely ill, hospitalized medical patients > 70 years. The primary study hypothesis is that acutely ill, hospitalized medical patients > 70 years in the ACE Unit's Prehab Program will have higher levels of ADL functioning at discharge than similar patients receiving usual care on conventional wards. A longitudinal, experimental study is proposed. During a 39-month enrollment period, 1530 medical patients > 70 years will be randomly assigned to two groups at the time of admission to University Hospitals of Cleveland: the intervention group will receive Prehab on the ACE Unit; the comparison group will receive usual care on conventional medical wards. Data will be collected at admission, discharge, 3 and 12 months after discharge, and every 12 months thereafter. The number of ADLs performed independently at discharge is the main outcome and will be determined by valid survey measures. Performance-based measures of physical function at discharge and other clinical, functional, quality- of-life, and financial outcomes will be monitored to characterize more fully the effects of Prehab. This interventional study will enhance understanding of functional decline and its prevention in hospitalized older patients.